TW201509784A - Process for draft control on feeding of elastic yarn - Google Patents

Abstract

A method for unwinding yarn is provided that allows for maximizing the draft of the yarn, while monitoring tension. The method includes providing a yarn package including elastic yarn; choosing a selected draft for said elastic yarn; unwinding the elastic yarn from the yarn package from a driven roll to yarn processing equipment at the selected draft which is determined by a ratio of a speed of the yarn at the yarn processing equipment to a speed of the driven roll; measuring tension in the elastic yarn; and providing an alarm when said tension reaches a critical level.

Description

Draft ratio control method for elastic yarn feed

The present invention relates to a method for maximizing utilization by controlling the draw ratio of the elastic yarn during the incorporation of the elastic yarn during the production of the textile.

Textiles such as fabrics including elastic yarns and non-woven fabrics can change products due to inconsistent tension when the yarn is fed into a textile or yarn processing equipment. It has been attempted to provide textiles of uniform quality by seeking to improve the consistency of yarn tension after the yarn has been unwound from the yarn package and fed into the yarn processing equipment.

For example, the problem of the change in tension is solved in U.S. Patent Application Publication No. 2007/0152093 A1 ("Hartzheim") by Hartzheim. Hartzheim solves this problem by introducing a tension control device that reduces the yarn tension change from the unwinding of the elastic yarn to the introduction of the yarn into the yarn processing equipment. This is achieved by a single loop tension control system.

Another example of tension control can be found in the international application WO 2007/00611 A1 ("Barea") of Barea. Barea also provides a solution for controlling tension during yarn processing by providing a two-loop tension control device for providing constant yarn tension to improve tension control.

Although the tension control device is suitable for maintaining the tension uniformity of the elastic yarn, it is not suitable. Used in the case where a change in tension can provide a commercially acceptable product. For certain textile products, such as sanitary articles and diapers, which may include fabrics or non-wovens, it is equally important and in some cases more important to maximize and maintain the consistent draw ratio of the elastic fibers to maximize utilization and yield. aims. There is a need for a method to achieve the goal of maximizing the draw ratio of the elastic yarn while also reducing or eliminating the downtime of the yarn processing equipment caused by breakage caused by unacceptable spikes in yarn tension.

When the yarn is used at the selected draw ratio, the textile manufacturer has the ability to maximize the production of the textile product. This allows for the most efficient use of each yarn package. Therefore, when the tension reaches an unacceptably low level, the draw ratio of the yarn can be increased.

The draw ratio of the elastic yarn can be maximized to improve the yield by monitoring and adjusting the tension spike or while the yarn tension reaches a critical level by unwinding the elastic yarn from the yarn package suitable for the yarn process. Unwinding includes: (a) providing a yarn package comprising elastic yarns; (b) selecting a selected draw ratio for the elastic yarn; (c) self-driving the elastic yarn at a selected draw ratio Unwinding from the yarn package to the yarn processing equipment, the draw ratio being determined by the ratio of the speed of the yarn of the yarn processing equipment to the speed of the drive roller; (d) measuring the elastic yarn Tension; (e) provide an alarm when the tension reaches a critical level.

The selected draw ratio can be the desired maximum draw ratio or other draw ratio desired for the desired product to be produced by the yarn processing equipment. The alarm can provide any of a variety of purposes, such as notifying the operator that a yarn breakage will occur, notifying the operator that the yarn tension should be reduced, and/or, in particular, providing a signal that will automatically adjust the yarn tension.

1‧‧‧ spool

2‧‧‧ spool

3‧‧‧ wire guide

4‧‧‧Drive roller

4A‧‧‧Rotating components

4B‧‧‧Electric motor/rotary element motor

5‧‧‧Tensor

6‧‧‧Microprocessor/Microprocessor type control circuit or unit

7‧‧‧Second sensor

9A‧‧‧Rotary component speed signal / speed signal

9B‧‧‧Line speed signal

10‧‧‧Device

12‧‧‧Control loop

F‧‧‧Yarn

T‧‧‧Textile Machine

Figure 1 is a schematic illustration of a device in accordance with the present invention.

A method for unwinding an elastic yarn comprises: (a) providing a yarn package comprising an elastic yarn; (b) selecting a selected draft ratio for the elastic yarn; (c) selecting the draft ratio Unwinding the elastic yarn from the drive roll from the yarn package to a yarn processing apparatus, the selected draw ratio being the speed of the yarn by the yarn processing apparatus and the speed of the drive roll The ratio is determined; (d) the tension of the elastic yarn is measured; (e) an alarm is provided when the tension reaches a critical level. This criticality can be a critical high tension level or a critical low tension level.

This yarn unwinding method for yarn processing or textile manufacturing equipment is suitable for a variety of different end uses or applications. A suitable unwinding method is called over end unwinding, also known as over end take-off (OETO). In the axial withdrawal method, the wire package is fixedly mounted on the unwinding frame such that the rotation axis of the package points in the general direction of the path through which the wire passes when the wire is pulled out of the package. However, in the axial unwinding method, the wire package does not rotate with the wire being pulled out from the package. In fact, the line is off the spool at the end of the spool. As the line leaves the spool, the exit track rotates around the circumference of the spool, so the path initially passed by the line is essentially rotational. At lower speeds, the line just crossed the 12 o'clock position on the bobbin and landed at 6 o'clock. At higher speeds, the line rotation effect is a centripetal force that acts substantially perpendicularly to the overall direction of travel of the line, whereby the line exits the spool and looks very much like a loop, skipping or ring or balloon activity. All such activities are intended to be included in a line of activities known as "loping" activities. Such pulsating activities must be controlled to reduce the degree of oscillation so that the line can be guided under controlled tension and in the direction of the predetermined path, in a manner to be transmitted, under controlled and generally constant (but variable) tension levels. Feed into the manufacturing process. In terms of achieving a generally constant degree of tension, the inherent tension peaks and other tension changes that are inherently distributed in the axial direction must be dissipated within the unwinding and feeding mechanisms.

Because the spool is fixed in position, the operator can tie the end of the first active spool to the front end of the next reserve spool so that when the spool is used up, the end of the spool is automatically transferred to the feed. Reserve the spool so that it does not need to be terminated for the spool Manufacturing process. Thus, the axial feed inherently avoids the waste of the wire on the replacement spool that has not been completely exhausted as indicated above and the shutdown, start-up time associated with such spool replacement. Therefore, axial feed represents built-in cost savings associated with material use and output output, whereby axial unwinding is desirable for unwinding the viscous wire and feeding such viscous wires into the manufacturing process. Technology. Additives for reducing the viscosity of yarns are also known. Some aspects of the yarn may include an anti-stick additive.

The invention will be more apparent from the following description, which is provided by way of non-limiting example and wherein the sole figure is a schematic representation of a device of one embodiment.

Referring to the figure, the device of the present invention is used to control the feeding of the yarn F into the textile machine T, such as a diaper production machine, that is, such a textile machine, wherein the respective yarns processed by the machine are unwound from the respective spools It is located at a distance that can vary from one meter to several tens of meters. In this example, the yarn F is unwound from the bobbin 2 connected to the other bobbin 1 in a known head-to-tail manner. This allows the yarn to be continuously processed by the textile machine to avoid stopping when the spool is empty. The yarn can be unwound by the axial yarn drawing method described above. After leaving the spool 2, the yarn F passes through a conventional wire guide 3 which can be positioned on the front faces of the two spools 1 and 2 such that the axis of the spool coincides with the center of the wire guide, thereby allowing the first The spool is periodically rotated and the two spools are unwound. After cooperating with the wire guide 3, the yarn F cooperates with the device 10 for measuring tension and adjusting the yarn draw ratio. This device 10 of the known type comprises in the example shown in the figures a drive roller 4 comprising a rotary element 4A on which the side of the yarn F is driven by its own electric motor 4B (for example brushless type), and common Tension sensor 5. These components 4 and 5 of the device 10 are connected to a control circuit or unit, such as a microprocessor type control circuit or unit 6, which can adjust the yarn draw ratio based on the tension data measured by the sensor 5. The yarn draw ratio is calculated and can be controlled by a microprocessor 6, which is coupled to the rotary element speed signal 9A and the line speed signal 9B. The speed signal (9A) is obtained from the rotary element motor (4B) and compared to the line speed signal (9B). The control algorithm (control loop 12) sets the speed of the rotary element motor (4B) to a predetermined setting that is typically part of the line speed Fixed point. In this way, the elongation of the elastic strand will be managed as the primary control loop.

The elongation of the management line is the primary control that allows the garment/diaper producer to maximize the yield of the elastic strand (the consumption is minimized). The set point and measurement results of the tension control loop can be used to fine tune the main yarn elongation control loop and evoke an alarm as needed to avoid line stoppages due to wire breakage.

An alarm is triggered when the microprocessor 6 senses the critical tension level. This can be a visible alarm, an audible alarm or a signal. When the alarm provides a signal, it can reduce the tension of the elastic yarn draft by increasing the speed of the drive roller. Alternatively, the drafting can be reduced by reducing the speed of the yarn processing equipment.

The second sensor 7 selected as appropriate may also be used in conjunction with or in conjunction with the sensor 5. When the second sensor 7 replaces the sensor 5, it provides the same function as described above. When the second sensor 7 is included in addition to the sensor 5, it provides an additional point of tension in the induction wire, which is transmitted to the microprocessor 6 to provide an alarm to adjust the yarn draw ratio or signal.

The elastic yarn can be any suitable elastic yarn such as an elastic rayon, a lastol or a polyester bicomponent fiber such as LYCRA® T400® fiber from INVISTA, Wichita, KS.

The draw ratio can be any suitable draw ratio for the yarn processing/manufacturing equipment. Examples include where the draw ratio is from about 1.5 to about 5.5, or from about 2.5 to about 5, or from about 3 to 4. The selected draw ratio can be the maximum draw ratio of the elastic yarn.

The critical high tension level signals the occurrence of yarn breakage, which can cause downtime of the yarn processing equipment. The critical high tension level is about 0.1 gmf/dtex or more than 0.1 gmf/dtex. The critical low tension level can be about 0.02 gmf/dtex.

The method of some embodiments may also include: (f) measuring the tension after decreasing the draw ratio; and (g) increasing the draw ratio to a selected draw ratio after reducing the tension below the critical point.

Although the present invention has been described as a preferred embodiment of the present invention, it will be appreciated by those skilled in the art that changes and modifications may be made without departing from the spirit of the invention, and all such changes and Improvements are included within the true scope of the invention.

1‧‧‧ spool

2‧‧‧ spool

3‧‧‧ wire guide

4‧‧‧Drive roller

4A‧‧‧Rotating components

4B‧‧‧Electric motor/rotary element motor

5‧‧‧Tensor

6‧‧‧Microprocessor/Microprocessor type control circuit or unit

7‧‧‧Second sensor

9A‧‧‧Rotary component speed signal / speed signal

9B‧‧‧Line speed signal

10‧‧‧Device

12‧‧‧Control loop

F‧‧‧Yarn

T‧‧‧Textile Machine

Claims (13)

A method for unwinding an elastic yarn from a yarn package suitable for use in a yarn process comprising: (a) providing a yarn package comprising an elastic yarn; (b) selecting a selected draw ratio for the elastic yarn; (c) unwinding the elastic yarn from the drive roll to the yarn processing apparatus at the selected draw ratio, the selected draw ratio being the yarn by the yarn processing apparatus The ratio of the speed to the speed of the drive roller is determined; (d) the tension of the elastic yarn is measured; (e) an alarm is provided when the tension reaches a critical level. The method of claim 1, wherein the criticality is a critical high tension level or a critical low tension level. The method of claim 1, wherein the draw ratio is from about 1.5 to about 5.5. The method of claim 2, wherein the critical high tension level is about 0.1 gmf/dtex or more than 0.1 gmf/dtex. The method of claim 2, wherein the critical low tension level is about 0.02 gmf/dtex. The method of claim 1, wherein the alert is an audible alert. The method of claim 1, wherein the alarm provides a signal for reducing the tension of the elastic yarn draft by increasing the speed of the drive roller. The method of claim 7, wherein the signal for reducing the draw ratio comprises automatically adjusting the draw ratio when the tension reaches the critical level. The method of claim 7, wherein the draft ratio is reduced by reducing the speed of the yarn processing apparatus. The method of claim 7, further comprising: (f) measuring the tension after decreasing the draw ratio; and (g) increasing the draw ratio to the place after reducing the tension below the critical point Choose the draw ratio. The method of claim 1, wherein the elastic yarn comprises an anti-adhesive additive. The method of claim 1, wherein the selected draw ratio is a maximum draw ratio of the elastic yarn. The method of claim 1, wherein the alarm alerts the operator that the elastic yarn may break.